[AMD Official Use Only - General]

Hello Boris,

quoted

+static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) {
+	unsigned long vaddr, paddr = pfn << PAGE_SHIFT;
+	struct rmpentry *entry, *large_entry;

.> +

quoted

+	if (!pfn_valid(pfn))
+		return ERR_PTR(-EINVAL);
+
+	if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+		return ERR_PTR(-ENXIO);

That test should happen first.

Ok.

quoted

+	vaddr = rmptable_start + rmptable_page_offset(paddr);

Wait, what does that macro do?

It takes the physical address and gives the offset from the beginning of the RMP table in VA space?

So why don't you do

entry = rmptable_entry(paddr)

instead which simply gives you directly the entry in the RMP table with which you can work further?

Instead of this macro doing half the work and then callers having to add the RMP start address and cast.

And make it small function so that you can have typechecking too, while at it.

Ok, I will add a new corresponding rmptable_entry() function here, should be usable for getting the large
RMP entry below too.

quoted

+	if (unlikely(vaddr > rmptable_end))
+		return ERR_PTR(-ENXIO);
+
+	entry = (struct rmpentry *)vaddr;
+
+	/* Read a large RMP entry to get the correct page level used in RMP entry. */
+	vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK);
+	large_entry = (struct rmpentry *)vaddr;
+	*level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry));
+
+	return entry;
+}
+
+/*

diff --git a/include/linux/sev.h b/include/linux/sev.h new file mode 

100644 index 000000000000..1a68842789e1

--- /dev/null
+++ b/include/linux/sev.h

Why is this header in the linux/ namespace and not in arch/x86/ ?

All that stuff in here doesn't have any meaning outside of x86...

Yes, makes sense to move it to arch/x86.

Thanks,
Ashish